Stud-framed walls are commonly used to enclose residences, offices and other structures. Stud-framed walls are also used to subdivide residence, offices and other structures into rooms within an outer enclosure. Basically, a stud-framed wall comprises a plurality of vertical studs positioned between a lower plate and an upper header. In wood-framed structures, the lower plate and the upper header each comprise one or more horizontally positioned lengths of lumber. The bottom and top ends of solid wood vertical studs are nailed or otherwise fastened to the lower plate and to the upper header. In metal-framed walls, the lower plate and the upper header are replaced with U-shaped channels; and the vertical studs comprise so-called C-shaped metal studs. Each metal stud has a web that defines the width of the stud and a flange that defines the “thickness” of the stud. Each metal stud further includes a lip/return that extends inward for a short distance from each flange in parallel with the web to increase the rigidity of the metal stud. The metal studs are secured to the upper and lower U-shaped panels by sheet metal screws or other suitable fasteners. Metal studs are available in various gauges ranging from 20 gauge (0.033 inch thickness) to 12 gauge (0.097 inch thickness).
After the framing of a wall is completed, the walls are covered with wall panels by securing the wall panels to the vertical studs and to the upper and lower channels. In many common wall structures, the wall panels comprise conventional wallboard panels such as drywall. Drywall, which is also known as gypsum board and plasterboard, commonly comprises a noncombustible core of gypsum or other suitable material with a paper backing on the front and back surfaces and on the edges. The wallboard panels described herein modify conventional drywall by including a thin sheet of metal on the back surface of the gypsum core. The thin sheet of metal is adhesively secured to the gypsum core under pressure such that the sheet of metal permanently attached to the gypsum core and provides a uniformly smooth rear surface. The sheet of metal has approximately the same planar dimensions as the gypsum core except that the horizontal and vertical dimensions are slightly smaller than the corresponding dimensions of the gypsum core. With the sheet of metal centered on the gypsum core, the edges of the sheet of metal are displaced inwardly from the edges of the gypsum core by approximately ¼ inch. Accordingly, the metal-backed wallboard panel can be handled safely in view of the rim of the gypsum core around the metal edges. The metal-backed wallboard panel is described in more detail in U.S. Pat. No. 5,768,841, which is incorporated herein by reference in its entirety.
A typical wall comprises a plurality of wall panels positioned adjacent to each other side-by-side with the long edges of each panel oriented vertically. In such installations, a vertical seam between two horizontally adjacent wall panels is aligned with a vertical stud such that both wall panels are secured to the stud and such that the vertical seam is blocked entirely by the vertical stud. In certain wall installations, the wall panels may be stacked with one panel positioned above another panel. In such installations, a horizontal seam is formed between two vertically adjacent wall panels. The horizontal seam extends from one vertical stud to an adjacent vertical stud. The front portion of the seam on the exposed front sides of the wall panels may be covered with wallboard joint tape and joint compound; however, the rear portion of the seam on the sides of the wall panels against the studs remains open. Furthermore, the horizontal edges of the wall panels between adjacent vertical studs have no underlying support. Absent such support, the portions of the two adjacent wallboard panels between adjacent wall studs may move with respect to each other and dislodge and tape and compound forming the front seam. In wood-frame wall structures, the rear portion of the seam may be covered and the horizontal edges of the wall panels may be supported by adding a horizontal brace between each pair of adjacent wall studs. Such a brace may be easily added to the wall structure by toenailing the brace to each of the adjacent wall studs. However, such braces are not easily added to a metal-framed wall structure. The lip/return of a typical C-stud does not provide sufficient area to allow a horizontal brace to be attached.